Development of Self-Organized Polymeric Lewis Acid-Catalysts for the Zero-Emission Synthesis of 2-Amino Alcohols

β-Amino alcohols are versatile synthetic intermediates for a wide range of biologically active natural and unnatural products. They can also serve as good chiral ligands for some asymmetric metal complex catalysts. The nucleophilic ring-opening of epoxides with an amine is one of the most efficient routes to obtain such β-amino alcohols with 1,2-trans stereochemistry. Therefore, various homogeneous catalysts have been developed for this transformation. Meanwhile, the development of efficient heterogeneous catalysts that can be easily prepared, recovered, and reused without losing their activities has currently received much attention from a practical and environmental point of view, and not a few such reusable heterogeneous catalysts （e. g. , supported on inorganic materials or insoluble polymers） have been developed. In general, however, they tend to show lower catalytic activities and selectivities compared to the corresponding homogeneous one, and the preparation of them are often tedious.     

Alkylation of toluene with 1,3-pentadiene over silica supported aluminum chloride catalyst in an extracting-distilling reactor

The alkylation of toluene with 1,3-pentadiene to produce pentyltoluene is designed to obtain 2,6-dimethylnaphalene for the monomer production of 2,6-naphthalene dicarboxylic acid. The possibility of the reaction is examined by the thermodynamics of the alkylation reaction using Thinh’s group contributions method, and tested over silica supported aluminum chloride catalyst in a newly developed extracting?distilling reactor. The thermodynamics calculation results show that the alkylation reaction is exothermic and can proceed at 298?350 K under normal pressure with an equilibrium constant higher than 106. Based on the thermodynamic calculation and the properties of the reactants and product, the extracting-distilling reactor was designed to allow 1,3-pentadiene to react with toluene at much lower temperature than the boiling point of toluene at the catalyst site. The alkylation product, which has a higher boiling point than that of toluene, is transferred from the catalytic site into the toluene bath and collected. The experimental results show that the reactor functions as designed and promotes the selectivity of the alkylation reaction close to 100%. The effect of raw material ratio of toluene to 1,3-pentadiene and reaction time are discussed in this paper. The suitable catalytic reaction conditions are as follows: at reaction temperature of 338 K and ambient pressure, the reactant ratio of toluene to 1,3-pentadiene is 5:1 for a six-hour reaction.     

Synthesis of Fine Chemicals by the Conjugate Addition of Nitroalkanes to Electrophilic Alkenes

It is well known the ability of primary and secondary nitroalkanes to generate carbanions （under basic conditions） strongly stabilized by the electron-withdrawing effect of the nitro group. Thus, the main use of nitroalkanes is devoted to the generation of new carbon-carbon bonds through two principal approaches （Scheme 1） ： （i） reaction with carbonyl derivatives （nitroaldol-Henry-reaction）, and （ii） Michael addition to electron poor alkenes.     

Macromolecules Mimicking Backbones of Nucleic and Teichoic Acids.Synthesis,Some Properties and Applications

1 Results Several methods have been elaborated in this laboratory allowing preparation of macromolecules with phosphodiester bonds,and having sequence of atoms similar as in the chains of biomacromolecules - nucleic or teichoic acids (TA),namely:-(C)n-O-PO-,where n=2 (for teichoic acids) or 3.These methods,to be discussed in the lecture,are based on the ring-opening polymerization,transesterification,and recently elaborated direct addition of phosphoric acid to diepoxides.For the first time an attempt has been made to directly reacting phosphoric acid with diols in the presence and absence of catalysts.The major side reaction,preventing high molar mass polymers formation,results from dealkylation,i.e.nucleophilic attack of the OH groups on the C atom,instead attack on the P atom.The other two methods allowed reaching high molar mass macromolecules,with Mn up to 105.Following these studies phosphorylation of polymers with side groups containing -OH groups were studied and a series of diblock copolymers with ionic and nonionic blocks were prepared.     

Photo Catalytic Oxidation of Alcohols in Water under Natural Weathering Conditions in the Presence of Bromo Source

1 Results The oxidation of alcohols into the corresponding carbonyl compound is one of the most important functional group transformation in organic synthesis[1]. Traditionally,such transformations have been performed with stoichiometric inorganic oxidant or other high valent metal oxidant[2]. Despite a variety of systems for the catalytic oxidation of alcohols have been developed,there is ongoing interest in the search for new efficient and environmental friendly oxidation system.To the best of our knowledge,there is no literature report on the oxidation of alcohols using Oxone as oxidant in the catalytic mount of HBr in water under solar light.A typical procedure was carried out as follows: In an aqueous solution of alcohols (1 equiv.),Oxone (0.9 equiv.) and HBr (0.2 equiv.) was added.The mixture was stirred for 4h under illumination of sunlight.After completion of the reaction,the mixture was analyzed by GC/MS.Benzyl alcohol was readily converted into corresponding acid with 97% selectivity.Cyclohexanol and 4-methylbenzhydrol were completely transformed to the corresponding ketones with 100% selectivity.     

A Convenient Method for the Oxidation of Alcohols with KMnO_4 to Their Corresponding Carbonyl Compounds in Ionic Liquid Media

1 Results Carbonyl compounds constitute an important group of molecules in organic chemistry,which appears in pharmaceuticals,dyes and industrially important chemicals[1-2].The oxidation of alcohols to the corresponding carbonyl groups is a fundamental transformation in organic chemistry and industrially important[3].There is considerable interest in the use of room temperature ionic liquids as promising substitutes for volatile organic solvents.The ambient-temperature ionic liquids,especially those based on 1,3-dialkylimidazolium cations,have been emerged as promising green solvents in recent decades[4].Some of the advantages of using ionic liquids in catalytic reactions are connected with the lack of a measurable vapor pressure.Products can be easily distilled out of the reaction mixture and the impact on the environment and operating personnel is dramatically reduced.In addition,due to the great choice of different ionic liquids,the solvent properties may be tuned to suit a particular application.In order to investigate such oxidation reactions in ionic liquids; the selective oxidation of alcohols to aldehydes was selected as a model reaction.     

Green chemistry: C-C coupling and asymmetric reduction by innovative catalysis

A catalytic method has been developed, which allows aryl halides to couple with various electron-rich olefins to give 1,1＇-substituted olefins. The palladium-catalysed coupling in ionic liquid solvent proceeds with high efficiency and remarkable regioselectivity without the need for any costly or toxic halide scavengers. Parallel to this, an environmentally-appealing method for the asymmetric reduction of ketones has been established, with which a variety of chiral alcohols can be accessed with high enantioselectivity in water with no need for any organic solvents. The same chemistry has been explored for the reduction of aldehydes, which is shown to be fast and highly chemoselective. These methods add new tools to the armoury of synthetic chemists.     

Green chemistry: C-C coupling and asymmetric reduction by innovative catalysis

A catalytic method has been developed, which allows aryl halides to couple with various electron-rich olefins to give 1,1’-substituted olefins. The palladium-catalysed coupling in ionic liquid solvent proceeds with high efficiency and remarkable regioselectivity without the need for any costly or toxic halide scavengers. Parallel to this, an environmentally-appealing method for the asymmetric reduction of ketones has been established, with which a variety of chiral alcohols can be accessed with high enantioselectivity in water with no need for any organic solvents. The same chemistry has been explored for the reduction of aldehydes, which is shown to be fast and highly chemoselective. These methods add new tools to the armoury of synthetic chemists.     

JWA, a novel microtubule－associated protein, regulates homeostasis of intracellular amino acids in PC12 cells

Our previous studies demonstrated that JWA,a novel retinoic acids responsive and cytoskeleton related gene, is associated with cell differentiation and apoptosis. In the present study, to elucidate if the JWA is a novel kind of microtubnle-associated proteins (MAPs) and functiona llylink to microtubule, we first successfully identified JWA from the physically purified MAPs complex of rat braint issues. The results of co-immunoprecipitation, gene transfection and immunofluorescence microscopy assays from HBE and NIH3T3 cells provide strong evidence for a linkage between JWA and β-tubulin. In general, JWA is stably binding to β-tubulin whenever microtubule is polymerized or not,and it may be critical to the mitosis process. In addition, by use of the antisense oligonucleotides technique, we also showed that JWA is a negative modulator on intracellular amino acids in PC12 cells. Further analysis indicated that JWA selectively regulates both taurine, an inhibitory aminoacid, and glutamate, an excitatory amino acid. In conclusion,JWA is not only structurally associated, but also a novel functional MAP.     

In-situ secondary growth of nanocube-based Prussian-blue film as an ultrasensitive biosensor

A regular nanostructure has been widely confirmed to result ina marked improvement in material performance in biosensing applications.In the present study,a regular nanostructured Prussian blue(PB) film with two heterogeneous crystal layers was synthesized in-situ using a secondary growth method.A PB seed layer was first controlled to form uniform cube-like crystal nuclei through an ultrasonic reaction with a single reactant.Then,well-defined 100 nm PB nanocubes were further crystallized on this seed layer using a self-assembly approach.In order to accelerate the electron transfer rate during the enzyme reaction for glucose detection,the graphene was used as the main cross-linker to immobilize glucose oxidase on the PB film.The as-prepared biosensor exhibited high electrocatalysis and electron conductivity for the detection of trace glucose with a sensitivity of141.5 μA mM~(-1) cm~(-2),as well as excellent anti-interference ability in the presence of ascorbic acid and uric acid under a low operation potential of-0.05 V.     

Mechanism of intramolecular mixed anhydride formation as intermediates in the reactions of N-phosphorylamino-acids──An MNDO research

N-phosphoryl-α-amino acids can react to form esters, peptides, phosphoryl ester-exchanged products and phosphoryl group migration products under mild conditions, which are very important in researches on arohebiont. It has been proposed that intramolecular mixed carboxylic-phosphoric anhydrides (IMCPAs) might be the common intermediates of the reactions, which are difficult to be experimentally observed because of their high activity. In this note, it has been revealed, by means of MNDO, that the IMCPAs are situated at the relatively minimal points of the potential surface and can form in a non-synchronous concerted reaction pathway that passes through a transition state with a hydrogen-bond-bridge structure. The results give a successful explanation to the structure and formation of IMCPAs and their ability to promote the various reactions mentioned above.     

Gold nanorod translocation through a solid-state nanopore

Recently, nanopores have been used in an essential technique for detecting single molecule with high sensitivity. The initial application of nanopores to DNA and RNA sequencing has been expanded to sensing pro- teins and nanoparticles, including Bovine serum albumin, silica nanoparticles, polystyrene beads, and others. In our study, for the first time, a positively charged gold nanorod was investigated using a solid-state nanopore device. Various gold nanorods passed through the nanopore with different current blockages and duration times, providing a measurement of the nanorod diameter, length, and charge. Our findings indicate that nanopore sensing might be a new method for characterizing the size, shape, and charge of nanoparticles.     

Enzyme-Mediated Hydrolysis of Poly（ethylene glycol）-Supported Carbonates

Enzymatic kinetic resolution of racemic alcohols or esters is known as a useful method for the preparation of optically active secondary alcohols. However, the work-up including the separation of the mixture of the remaining substrate and the resulting compound spend a lot of time and waste much amount of solvents. On the other hand, organic synthesis based on polymer supports has made rapid progress. Although the methodology is potentially useful for the easy separation of compounds obtained by the enzymatic reaction, there have been relatively few reports on enzymatic resolutions of using a polymer so far. We have noticed that using a watersoluble polymer could be suitable for enzymatic transformation. Here, we report the first example of an enzyme-mediated enantioseleetive hydrolysis of poly（ethylene glycol）（PEG）-supported substrates with a carbonate moiety to afford optically active compounds, and the method enables us to achieve the easy separation of the products. See Scheme 1.     

Enzyme-Mediated Hydrolysis of Poly(ethylene glycol)-Supported Carbonates

1Introduction Enzymatic kinetic resolution of racemic alcohols or esters is known as a useful method for the preparation of optically active secondary alcohols. However, the work-up including the separation of the mixture of the remaining substrate and the resulting compound spend a lot of time and waste much amount of solvents. On the other hand, organic synthesis based on polymer supports has made rapid progress. Although the methodology is potentially useful for the easy separation of compounds obtained by the enzymatic reaction, there have been relatively few reports on enzymatic resolutions of using a polymer so far. We have noticed that using a watersoluble polymer could be suitable for enzymatic transformation. Here, we report the first example of an enzyme-mediated enantioselective hydrolysis of poly(ethylene glycol)(PEG)-supported substrates with a carbonate moiety to afford optically active compounds, and the method enables us to achieve the easy separation of the products[1]. See Scheme 1.     

Studies on the interactions of 2,5-diphenyl 1,3,4-oxadiazole and 2,5-diphenyl 1,3-oxazole with β-cyclodextrin

Interactions of 2,5-diphenyl 1,3,4-oxadiazole (PPD) and 2,5-diphenyl 1,3-oxazole (PPO) with β-cyclodextrin (β-CD) are studied by 1H-NMR and steady-state fluorescence measurements, and the stoichiometries and the association constants are estimated. It is found that the hydrophobic interaction is the main driving force for the formation of inclusion complexes of PPD and PPO with β-CD. In the presence of aliphatic alcohols (from 1-propanol to 1-pentanol), PPD and PPO transfer from the CD cavity to the aqueous phase. Quenching experiments of PPD and PPO by iodide further prove the above conclusions. The results suggest that stereo effect is the crucial factor to the inexistence of nanotube in PPD (or PPO)-β-CD systems.     

Solvothermal synthesis of crystalline carbon nitrides

A solvothermal reaction of anhydrous C3N3Cl3 and Li3N using benzene as the solvent has been carried out to prepare crystalline carbon nitrides successfully at 350 ℃ and 5-6 MPa ,X-ray diffraction (XRD) indicated that the major part of our brown sample was mainly composed of α－C3N4 and β-C3N4 with lattice parameters of a=0.65nm,c=0.47 nm for α－C3N4 and α=0.644nm,c=0.246nm for β-C3N4,which match the latest ab-initio calculations quite well,The N/C ratio in the powder is about 0.66 The Fourier transform infrared spectroscopy (FTIR) and X-ray photoeletron spectroscopy (XPS) analyses suggested the presence of both single and double carbon-nitrogen bonds,The kinetics effect of our solvothermal reaction to prepare crystalline carbon nitrides are also discussed chiefly.     

Manganese (Ⅲ) Acetate:A Versatile Reagent in Organic Chemistry

1 Results Free radical reactions have become increasingly important,as well as a very attractive tool,in organic synthesis within the last two decades,due to their powerful,selective,specific,and mild reaction abilities.Mn(OAc)3 mediated oxidative free radical reactions have been extensively developed in the last twenty years[1,6].Numerous regio-,chemo-,and stereoselective synthetic methods have been developed in both inter-and intramolecular reactions,and have detailed the progress of Mn(OAc)3 mediated oxidative free radical reactions. The selective oxidation of enones led to α′-acetoxy-enones by Mn(OAc)3 oxidation.In general,Mn(OAc)3 oxidations are characterized by higher α′-regioselectivity and chemical yields,and milder reaction conditions,in turn tolerating many sensitive functional groups.The use of Mn(OAc)3 in combination with other carboxylic acids or manganese(Ⅱ) carboxylates extends this methodology to the preparation of a variety of α′-acyloxyenones that are otherwise inaccessible in a one-step procedure.We developed a general method for the synthesis of biaryls starting from arylhydrazines and aromatic solvents in the presence of Mn(OAc)3.We showed for the first time that Mn(OAc)3 is a versatile reagent for the generation of aryl radicals from arylhydrazines.In a subsequent work,we extended this method for the synthesis of heterobiaryls,which was able to be achieved in thepresence of heteroaromatic compounds such as furan and thiophene. Another biaryl coupling reaction starting with arylboronic acids,mediated by Mn(OAc)3,was developed.The treatment of arylboronic acids with Mn(OAc)3 in benzene at reflux temperature afforded the corresponding biphenyl in high yields[7].     

MOLECULAR DESIGN STUDY ON THE NEW ORGANIC NONLINEAR OPTICAL MATERIALS

In this paper, the second-order nonlinear-optical coefficients of a series of conjugated substituted polyenes have been calculated by the semi-empirical CNDO/S-CI method, we have studied in detail the influence on the number of substituents, the location of the substituents and the conjugation length in molecules to the NLO coefficient β The results showed that the introduction of the electronic donor and acceptor groups and the increase in the distance between the substituents and the conjugated length may lead to enhanced NLO responses. It is also shown that the calculated ln β_(vec) is linear with the number of double bonds in planar and linear trans substituted polyenes. A saturation effect in substitution is also presented. Based on these discussion one can provide the theoritical guidelines for designing and synthesizing of molecules with larger NLO coefficients.     

The extremum principle of mass entransy dissipation and its application to decontamination ventilation designs in space station cabins

In terms of the analogy between mass and heat transfer phenomena, a new physical quantity, i.e. mass entransy, is introduced to represent the ability of an object for transferring mass to outside. Meanwhile, the mass entransy dissipation occurs during mass transfer processes as an alternative to measure the mass transfer irreversibility. Then the concepts of mass entransy and its dissipation are used to develop the extremum principle of mass entransy dissipation and the corresponding method for convective mass transfer optimization, based on which an Euler＇s equation has been deduced as the optimization equation for the fluid flow to obtain the best convective mass transfer performance with some specific constraints. As an example, the ventilation process for removing gaseous pollutants in a space station cabin with a uniform air supply system has been optimized to reduce the energy consumption of the ventilation system and decrease the contaminant concentration in the cabin. By solving the optimization equation, an optimal air velocity distribution with the best decontamination performance for a given viscous dissipation is firstly obtained. With the guide of this optimal velocity field, a suitable concentrated air supply system with appropriate air inlet position and width has been designed to replace the uniform air supply system, which leads to the averaged and the maximum contaminant concentrations in the cabin been decreased by 75% and 60%, respectively, and the contaminant concentration near the contaminant source surface been decreased by 50%, while the viscous dissipation been reduced by 30% simultaneously.     

Statically accelerated experimental simulation on the deterioration of dynamic strength of rock

In order to reveal the strength deterioration law of rock mass under an acidified environment, a series of experiments on strength deterioration and the environmental effect on marble and diabase under the conditions of three kinds of acids (H₂SO₄, HNO₃ and HCl) with three contents (1.0%, 5.0% and 10.0%) in a static fluid surrounding were carried out by single factor simulation. After the stones had been saturated in the above solutions for 90 days, an indoor weathering simulation had been observed for 300 days and its strength characteristics were measured under static/dynamic load and that results were compared with those under the natural condition. It is evident that the strength is emaciated greatly after the stones eroded by the liquids, whether under the static or dynamic load.